Switching device



Nov. 13, 1962- K. H. DATE SWITCHING DEVICE 3 SheetsSheet 1 Filed Oct. 14, 1960 pl hl u lv a INVENTOR. 759200 iii/way 0/472? BY Nov. 13, 1962 K. H. DATE SWITCHING DEVICE 5 Sheets-Sheet 2 Filed Oct. 14, 1960 INVENTOR. K6200 iii/we) D472- flrra/ewiy Nov. 13, 1962 K. H. DATE 3,06

SWITCHING DEVICE Filed Oct. 14, 1960 3 Sheets-Sheet 3 INVENTOR. gf zw Fla/vex 5972' B ilnited b tates Patent 3,664,107 SWITCHING DEVKQE Kazan Henry Date, South Milwaukee, Wis, assignor to McGraw-Edison ilornpany, Milwaukee, Wis, a corporation of Delaware Filed st. 14, 196i), Ser. No. 62,759 Claims. (Ql. 20017il) This invention relates to switching devices and, more particularly, to air disconnect switches.

it is the primary object of the invention to provide self-aligning stationary contact structure for an air disconnect switch.

This and other objects and advantages of the invention will become more apparent from the detailed description of the invention taken with the accompanying drawings in which:

FIG. 1 is a side elevational view, with parts broken away, of the load break disconnect switch embodying the instant invention;

FIG. 2 is a top plan view of the device shown in FIG. 1;

FIG. 3 is a top segmented view, partly in section, illustrating the various current interchange and anti-rebound structures according to the instant invention;

FIG. 4 is an elevational view, with parts broken away, of the disconnect switch self-aligning contact structure; and

FIG. 5 is a view taken along lines 55 of FIG. 4.

In general terms, the invention comprises a stationary contact jaw of an air disconnect switch comprising a body member having a recess formed therein, a helically wound, conductive current interchange member disposed in said recess with its helical axis lying in a plane sub stantially parallel to the direction in which the switch blade pivots and contact means one side in resilient rocking engagement with the spring member and engageable on its other side by the spring member.

Referring to the drawings in greater detail, the in vention is illustrated in connection with the combination of, an air disconnect switch, designated generally by the reference numeral 10, and a load interrupting device 11. The disconnect switch 19 includes a pair of parallel switch blades 12 pivotally mounted on a conductive hinge joint 14, which, in turn, is mounted atop a first porcelain bushing 15. A stationary contact jaw 18 is disposed atop a second porcelain bushing 2i and is engageable by the switch blades 12 when the latter are moved into their closed position seen in FIG. 1. Terminal pad 25 is also secured to the upper end of bushing 16 and is adapted to receive a line conductor (not shown). Contact jaw 18 may be provided with a releasable latch (not shown) for preventing unintentional movement of switch blades 12 under the influence of magnetic forces incident to heavy currents.

The hinge assembly 14 includes a base portion 22 afiixed to bushing 16 and a body portion 24 to which the switch blades 12 are hingedly mounted by means of a pivot bolt 26 and a nut 2'']. Current transfer between the body portion 24 of hinge member 14 and the switch blades 12, is accomplished by means of a pair of helically wound annular current interchange springs 28 composed of a suitable conductive material and disposed in a pair of annular grooves 29 formed in the lateral sides of body portion 24.

Body portion 24, switch blades 12, pivot bolt 26 and nut 27 are constructed and arranged so that the distance between the bottom of grooves 29 and the inner sides of switch blade 12 is less than the outside helical diameter of the current interchange springs 28. This forces the individual convolutions of springs 28 to lay over at an angle relative to their helical :axis whereby 2 the resiliency of said springs provides contact pressure with body portion 24 and switch blades 12. Thus, current transfer is eiiected between body portion 24 and switch blades 12, through a large number of parallel paths comprising the individual spring convolutions of springs 28. A more detailed description of the contact structure just defined may be found in copending application Ser. No. 847,263, filed October 19, 1959, and which is assigned to the assignee of the instant invention.

Referring specifically to FIGS. 4 and 5, the stationary contact jaw 18 is shown to include a body portion 34) and a base portion 32 which is afiixed to porcelain insulator 20. In addition, an interrupter mounting plate 33 is secured between base 32 and bushing 20 and includes an integral terminal pad 34 for connection to the other line wire (not shown).

Current interchange structure 35, for rendering contact jaw 18 self-aligning relative to the switch blades 12, is disposed in recesses 36 formed in the opposite sides of the body portion 39 of stationary contact jaw 18 and each includes a helically wound conductive current interchange spring 37 and a contact plate 38. Each of the current interchange springs 37 is disposed in a circular groove 49 formed on the inner surface of recess 36. Contact plates 38 are also circular and each has an embossed rim 42 engageable with retaining rings 44 affixed to the peripheries of recesses 36 and which hold plates 38 in engagement with the convolutions of their associated current interchange springs 37.

A plurality of dimples 46 are formed in the outer surface of each of the contact plates 38 and extend toward the switch blade 12 to provide points of contact therewith.

The lower portion of each of the grooves 40 is V- shaped so that they will contact each of the convolutions of their associated springs at two points. In this manner, a pair of parallel current paths are provided through each spring convolution thereby substantially lowering the voltage drop across the interchange structure and also reducing the heat generated in the spring itself. Retaining rings 44; are so located relative to grooves 4t that the distance between contact plates 38 and the inner portion of grooves 40 is smaller than the outside helical diameter of the spring 37 so that each of the spring convolutions is forced to lay over at an angle relative to its helical axis. Here again, the inherent resiliency of springs 37 provides contact pressure with the contact plates 38 and the body portion 39 of contact jaw 18.

When the switch blades 12 are in their open position the current interchange springs 37 force contact plates 38 outwardly until the rims 42 engage the retaining rings 34-. This will allow the springs 37 to straighten out somewhat but the gap between contact plates 38 and grooves 43 will be insufficient to allow them to assume a normal position relative to their helical axes. When switch blades 12 are returned to their closed position they are guided into alignment with the current interchange structures 35 by slanting surfaces 43 formed on the upper end of body portion 30. When dimples 46 are engaged, each of the contact plates 38 will be forced inwardly toward grooves 4% thereby causing current interchange springs 37 to lay over at a greater angle which increases the contact pressure between dimples 46 and the switch blades 12 as well as between the current interchange springs 37 and the contact plates 38, on the one hand, and the body member 31 on the other.

It will be appreciated that the current interchange structure 35 just described allows a large degree of misalignment between switch blade 12 and stationary contact jaw 18 without a substantial reduction in its current transferring abilities because each of the contact plates 38 floats on its associated current interchange spring 37. As a result, the contact plate 38 are rockable as well as movable axially of grooves 49. In addition, because each of the contact plates 38 is providedwith three dimples 46, three points of contact with each of the switch blades 12 will be maintained even though the switch blades 12 are closed in at an angle relative to contact jaw 18.

From the foregoing it will be apparent that the current path through the disconnect switch 1%) is from terminal pad 25, through the body portion 24 of hinge member 14, the current interchange springs 28, the switch blades 12, the contact plate 38, the current interchange springs 37, the body portion 36, and out of the rear terminal pad 34.

Turning now to the load interrupter 11 it is shown to include a first quick break blade 56 pivotally mounted on one of the switch blades 12 and a second quick break blade 52 pivotally mounted in an arc chute 54 disposed adjacent the stationary contact jaw 18.

The are chute comprises a pair of complementary plates 55 of any suitable insulating material and each is preferably lined with a substance capable of evolving an arc extinguishing gas when subject to an arc, such as a fibre, synthetic resin, or the like. A spacer member 56 is provided between plates 55 and along three of the edges thereof for maintaining them in spaced relation when they are secured together by any suitable means, such as rivets 57. The are chute 54 is supported adjacent the stationary contact jaw 18 by a conductive supporting bracket 59 integral with the mounting plate 33 and extending upwardly therefrom.

The first quick break blade is pivotally mounted on one of the switch blades 12 by means of a hinge assembly 60 which is shown in FIG. 3 to include a rod 62 aifixed to blade 50 and a cylindrical housing 64 affixed to switch blade 12. Current is transferred between rod 62 and housing 64 by means of a pair of current interchange springs 66 disposed in a pair of annular V-in-cross-section grooves formed on the inner surface of housing 64. The depth of grooves 68 are less than the outside helical diameters of current interchange springs 66 so that each of the convolutions of said springs are forced to lay over at an angle relative to their helical axes. This provides bearing pressure between the springs 66 and the shaft 62 and sleeve 64. A torsion spring 74} surrounds housing 64 and engages the switch blade 12 and quick break blade 5% for biasing the latter into engagement with a resiliently mounted stop 72.

Stop 72 includes a massive head portion 73, a reduced waist portion 74 and a stem portion 76 which extends through an aperture 78 in switch blade 12. The base 79 of waist portion 74 is resiliently urged against the side of switch blade 12 by a compression spring 80 which surrounds stem portion 76 between the opposite sides of switch blade 12 and a washer 81 afi'ixed to the end of stem portion 76.

A hinge assembly 83 identical to the hinge assembly 60 is affixed to conductive bracket 59 and extends through one of the plates for pivotally supporting the second quick break blade 52 within arc chute 5 A torsion spring 86 in bearing assembly 83 (the end of which is shown in FIG. 1) resiliently urges the second quick break blade 52 against a stop member 83 substantially identical with stop member 72 and which is resiliently supported on bracket member 59 and extends through an aperture in the side of plate 55.

When the disconnect switch is in its closed position, shown by full lines in FIG. 1, the first quick break blade 56 is parallel to switch blade 12 and in engagement with stop 72. The second quick break blade 52 is in engagement with stop 88, also as shown by full lines in FIG. 1.

As the switch blades 12 are moved toward open position by exerting a force upon pull ring 90, the switch blades 12 will begin to move out of engagement with the stationary contact jaw 18. Prior to the point at which the switch blades 12 become disengaged from stationary contact jaw 18, the quick break blades 59 and'52 will engage thereby providing an auxiliary current path around stationary contact jaw 18. This auxiliary path is from terminal pad 25, through hinge member 14, switch blades 12, hinge assembly 61), quick break blades 58 and 52, hinge assembly 83, bracket member 59, and out terminal pad 34. After the auxiliary load path has been established, further movement or" switch blade 12 towards its fully open position disen-gages it from the stationary contact jaw 18.

Torsion springs 71} and 86 are so proportioned that as switch blade 12 rotates toward its open position, quick break blade Stl will remain in parallelism therewith and quick break blade 52 will be pivoted in a clockwise direction. This will continue until quick break blade 52 engages a resilient stop 92 identical with stops 72 and 88, described above, whereupon further rotation thereof is prevented. When blade 52 is in this position, indicated by the reference numeral 52 in FIG. 1, the torsion spring 36 will be fully loaded. Continued rotation of switch blade 12 will then cause relative rotational movement between switch blade 12 and quick break blade 58 until they achieve their intermediate positions shown by phantom lines and indicated by reference numerals 12 and ill respectively in FIG. 1. When blade 50 is in this position, the torsion spring 76 will also be fully loaded and the tips of blades 50 and 52 will just be in engagement. Additional pivotal movement of switch blades 12 will cause the tips of quick break blades 50 and 52 to disengage drawing an arc therebetween. Torsion springs and 86 will then cause the blades 56 and 52 to move rapidly in opposite directions and toward their respective stops 72 and thereby rapidly elongating the are so that interruption is enhanced. In addition, quick break blades 5% and 52 will part at a point between plates 55 so that the are will be confined and controlled within the arc chute 54.

In addition, the massive heads and the resilient mountings of stop members 72 and 88 will absorb the energy of quick break blades 50 and 52 respectively thereby eliminating the possibility that either will rebound which would bring them into proximity and thereby increase the possibility that the arc would be restruck.

Upon reaching its fully open position, the quick break blade 50 will again be in parallelism with switch blade 12 as shown by phantom lines and indicated by the reference numerals 50" and 12" in FIG. 1. The second quick break blade 52, on the other hand, will return to its initial position shown by full lines.

When the switch blade 12 is pivoted toward its closed position the quick break blades 50 and 52 will engage thereby re-establishing the auxiliary current path, prior to the engagement of the switch blades 12 with the stationary contact jaw 13. Also, the spring which biases stop 72 is made to exert a greater force than the spring which biases stop 88 so that as switch blades 12 are moved into their fully closed position, quick break blade 51) will force quick break blade 52 and stop 82 to deflect to their positions shown by phantom lines and indicated by the reference numerals 52" and 88" respectively. After the tip of blade 50 passes the tip of blade 52, the resilient mounting of stop 88 returns quick break blade 52 to its initial position shown by full lines. The device is thereby reset for the next operation. In this manner, also, the auxiliary load path is opened so that all of the current is carried through the disconnect switch 10. It can be seen, therefore, that current is carried through the quick break blades 50 and 52 only during an opening or reclosing operation. It will be appreciated, too, that resilient stops 72 and 83 perform the functions of absorbing the energy of the quick break blades and also for allowing the resetting thereof.

While the self-aligning contact structure is shown in conjunction with a particular load break disconnect switch it will be appreciated by those skilled in the art that it has application as well to any type of switching device wherein a movable switch blade engages a stationary contact jaw. In addition, while this contact structure has been illustrated in conjunctio .i with a pair of switch blades, it has application as well to a single bladed device wherein the current interchange means are disposed on either side thereof. Accordingly, although only a single embodiment of the invention has been shown and described, it is intended to cover in the appended claims all modifications and embodiments of the various aspects of the instant invention that fall within the scope of the invention.

I claim:

1. In a disconnect switch having a pair of spaced apart insulating bushings, a stationary contact jaw mounted on one of said bushings, switch blade means mounted on the other of said bushings and pivotal into and out of engagement with said contact jaw, said contact jaw including a body member having a pair of recesses formed therein, a helically wound, conductive, current interchange spring member disposed in each of said recesses with their helical axes lying in planes substantially parallel to the plane in which said switch blade means pivots, a distinct contact member disjoined from said body member and disposed adjacent each of said spring members, substantially all of the individual convolutions of said spring members being in engagement with said body member and their associated contact members to resiliently support said members for rocking engagement independent of said base member and to provide a current interchange path therebetween, said spring members also forcing said contact members into high pressure engagement with said switch blade means to provide self-aligning, high pressure electrical engagement between said body member and said switch blade.

2. In a disconnect switch having a pair of spaced apart insulating bushings, a stationary contact jaw mounted on one of said bushings, a pair of parallel interconnected switch blades mounted on the other of said bushings and pivotal into and out of engagement with said contact jaw, said contact jaw including a body member having a recess formed on each of the opposite sides thereof, a helically wound, conductive, current interchange spring member disposed in each of said recesses with their helical axes lying in planes substantially parallel to the planes in which said switch blades pivot, and a distinct contact member disjoined from said conductive base and disposed adjacent each of said spring means, substantially all of the individual convolutions of said spring members being in engagement with said body member and one side of their associated contact members to resiliently support said contact members for rocking engagement independent of said body member and to provide a current interchange path therebetween, said contact members each being engageable on its other side by one of said switch blades to provide self-aligning, high pressure, electrical engagement between said body member and said switch blades.

3. In a switching device having a stationary contact assembly and contact means movable into and out of engagement with said stationary contact assembly, said stationary contact assembly including stationary body means having recess means provided therein, a pair of helically wound conductive current interchange spring members disposed in spaced apart relation within said recess means, a pair of distinct contact members disjoined from said body means and each being disposed Within said recess means adjacent one of said spring members, means for holding said contact members in engagement with said spring members wherein the distance between said contact members and said body members is less than the normal outside helical diameter of said spring members whereby the individual convolutions of said spring members are forced to lay over so that substantially all of the individual convolutions of said spring member are in engagement with said body means and said contact members to resiliently support said contact members for rocking engagement independently of said body means and to provide a current interchange therebetween, said spring members forcing said contact members into electrical engagement with spaced apart portions of said movable contact means when the latter is in engagement with said movable contact assembly to provide self-aligning, high pressure, electrical engagement between said stationary contact assembly and said movable contact means.

4. In a switching device having a stationary contact assembly and contact means movable into and out of engagement with said stationary contact assembly, said stationary contact assembly including stationary body means having recess means provided therein, a pair of helically wound conductive current interchange spring members disposed in spaced apart relation within said recess means, the helical axis of each of said spring means lying in planes which are substantially parallel to a plane containing the movable path of said contact means, a pair of distinct contact members disjoined from said body means and each being disposed within said recess means adjacent one of said spring members, substantially all of the individual convolutions of said spring members being in engagement with its associated con-tact member and said body means to resiliently support said contact members for rocking engagement independently of said body means and to provide a current interchange therebetween, said spring members forcing said contact members into electrical engagement with spaced apart portions of said movable contact means when the latter is in engagement with said stationary contact assembly to provide selfaligning electrical engagement between said stationary,

contact assembly and said movable contact means.

5. In a switching device having a stationary contact assembly and elongate contact means movable into and out of engagement with said stationary contact assembly, said stationary contact assembly including body means having a pair of spaced apart, opposed recesses formed therein, a helically wound conductive current interchange spring member disposed in each of said recesses, the helical axis of each of said spring members lying in planes which are substantially parallel to a plane containing the movable path of said elongate contact means, a distinct contact member disposed in each of said recesses adjacent one of said spring members and disjoined from said body means, substantially all of the individual convolutions of said spring members being in engagement with said body means and its associated contact member to resiliently support said contact member for rocking engagement independently of said body means and to provide a current interchange therebetween, said spring members forcing said contact members into electrical engagement with opposed, spaced apart portions of said movable contact means when the latter is in engagement with said stationary contact assembly to provide self-aligning, electrical current interchange between said stationary contact assembly and said movable contact means.

References Cited in the file of this patent UNITED STATES PATENTS 1,966,234 Cox et al. July 10, 1934 2,063,954 Ramsey Dec. 15, 1936 2,226,385 Ramsey Dec. 24, 1940 2,709,739 Gilliland et al May 31, 1955 2,751,471 Wills June 19, 1956 2,948,794 Fjellstedt et al. Aug. 9, 1960 FOREIGN PATENTS 29,822 Great Britain Dec. 3, 1914 of 1913 133,830 Austria June 26, 1933 1,063,687 Germany Aug. 20, 1959 

